Jon, Someone had what they stated were NOS chrome knobs on eBay, but they looked like the reproduction piece that you presented; four ribs (coincidentally, they looked the same as the chrome reproduction knobs in my Rick's catalog). The originals in your first pic have five ribs. So I was wondering if the two were shaped the same or if they actually had different styles for the deluxe/standard interiors. One thing I did notice on them though is that they had the same ring pattern on top as the originals pictured here.